This invention relates to envelope printing equipment such as that used in envelope printing and processing machines. It particularly applies to a mailing machine that separates, feeds and transports mail along a feeding path that includes a moistening and sealing device prior to being printed with a postal indicia. The mail or envelope may have to be stripped in advance of moistening the flap at the moistening device; therefore, a stripper blade is employed to separate the flap from the body of the envelope. In the present invention, the apparatus and process include a vacuum plenum employed to hold the envelope flap down during advancement of the envelope through the system. The vacuum hold-down is used to insure that the flap is out of the way when the envelope""s leading end approaches the stripping blade, thereby preventing any potential jam.
The present invention involves an envelope processing machine such as a mailing machine. The mailing machine has been available in many forms, being able to process mail and envelopes of all sizes, and types since Arthur Pitney and Walter Wheeler Jr. of Pitney Bowes Inc. began developing these machines. The older equipment and that of the present age utilize a moistening device for the envelope or mail flaps. The moistening apparatus identified with the equipment depends upon being able to separate the envelope or mail flap from the body of the envelope. Once separated, a stripper blade may be utilized to keep the flap away from the body of the envelope, thereby allowing a moistening device to apply the necessary sealant or water to the glued portion of the flap.
The present invention is used in the new mailing equipment of today in order to prevent jams of the envelopes being transported through the mailing machine feeding path. In spite of the advancements sometimes seen in the prior art, there is still a severe tendency of the mailpiece and mailpiece flap (envelope flap) to easily jam in the mailpiece transport area. This especially happens at the stripper blade, typically used to separate the envelope or mailpiece flap from the body of the envelope. Unpredictable attitudes of the flap during the transport process will inevitably permit some portion of the mailpiece flap to catch on the wrong components. The intent is to have the flap smoothly transition through the area where the stripper blade is located. To do this requires firmly establishing the location of the flap during the transport process. Therefore, the present invention uses a vacuum plenum in order to hold the envelope flap down while the envelope moves downstream in the system thereby preventing any jam potential. The present invention has shown that it is possible to reduce jams at the stripper blade mechanism by positively positioning the envelope flap against a surface that guides the flap beneath the stripping blade. This insures that the stripping blade will be in position between the inside of the envelope flap and the body of the remainder of the envelope or mailpiece.
This new vacuum system is applied where stripping of the envelope flap needs to be accomplished reliably in order to optimize the performance of the machine, and for providing a properly sealed envelope.
The present invention provides an envelope flap stripping apparatus for mailing machines, or other business machines or equipment handling envelopes to be moistened. The invention includes an envelope transport system supported on a fixed structure or frame the fixed structure further supporting a vacuum plenum unit comprised of a chamber-like box that is sealed except where there are vacuum applying apertures. The vacuum plenum unit has a plenum cover mounted and secured to the chamber-like box. The plenum cover has a series of parallel apertures in the surface that are aligned along the envelope or mailpiece feed path to intercept an on-coming envelope or mail-piece. The series of parallel apertures are spaced apart to be generally parallel to a registration wall of the mailing machine structure while they are generally parallel to the feed deck of the mailing machine. There are a number of groups of apertures in the plenum that are larger than others, being strategically placed to open, hold and continuously acquire each envelope flap. The greater holding potential of the vacuum source is greater near the registration wall where the envelope flap is hinged, as well as at an outboard position relative to the registration wall of the machine. There is a greater need for additonal holding force at those locations. The vacuum applied through the plenum apertures grab and continue to acquire the envelope or mailpiece flap moving past the plenum unit so that the downstream stripper blade can properly enter the space between the body of the envelope and the envelope flap.
In another embodiment of the present invention, the envelope flap is held down by an application of negative pressure while a positive supply of pressure is applied to the inside surface of the opened envelope flap. This is another way to insure the envelope flap is aligned to an open position, in order to be intercepted by a stripper blade assembly.
In yet another embodiment of the present invention, there is a positionable plenum deflector that either directs the envelope to a non-stripping position, or to a stripping position. The plenum deflector holds the envelope flap to an open position while the envelope is advanced towards a receiving path that includes a stripper blade.